One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The first opportunity to plant skullcap in Riverside can be determined by looking at the USDA zone info.

Planting Calendar for Skullcap

Frost tolerance for skullcap:	Not tolerant of frost.
When to plant:	After the last frost.

You should not plant skullcap until after the last frost has passed because they do not do well in cold weather.

The earliest that you can plant skullcap in Riverside is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant skullcap and expect a good harvest is probably September. Any later than that and your skullcap may not have a chance to really do well. Starting your skullcap indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average the last frost is on February 15 in Riverside. In the coldest months of winter you can expect an average low temperature of 25°F.

Since the USDA zone info for Riverside is just an average the actual date of last frost can change quite a bit from year to year. Half of the time in Riverside you get a frost after February 15 so make sure that you are prepared to protect your skullcap if you have a late frost.

USDA Zone Info for Riverside

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°F

This means that on a really cold year, the coldest it will get is 25°F. On most years you should be prepared to experience lows near 30°F.

Plants to Grow in Riverside

You may be interested in your other planting guides for Riverside.